Places to find math:
|Type of site||Examples||Is it useful as a course?||Is it useful as a reference?||Is it fun?|
|Video lectures||Khan Academy, MIT OpenCourseWare, YouTube|
|Online books||Applied Topology and Geometry, Hatcher's topology book|
|Lecture notes||Online lecture notes|
|Encyclopedias||Wikipedia, PlanetMath, Wolfram MathWorld|
Will there be time when everybody keeps his stuff at his own site and all of these "communities", aggregators, middlemen die out?